Center delivery stoker



Nov. 17 1942.

R. L. BELKNAP CENTER DELIVERY STOKER Filed Feb. 20, 1940 .2 SheetS Sheet 2 Patented Nov. 17, 1942 CENTER DELIVERY STOKER Raymond L. Belknap, Schenectady, N. Y., assignor to The Standard Stoker Company, Incorporated, a corporation of Delaware Application February 2-0, 1940, Serial No. 319,876

6 Claims.

This invention relates to locomotive stokers.

In burning coal in a locomotive firebox, it is of prime importance that the fuel be burned as completely as possible within the firebox proper so that stack losses in the form of unburned fuel particles may be avoided. With the conventional manner of delivering coal to a point of distribution adjacent the back head of the locomotive it has been found in certain instances, due to the heavier draft along the back head, that a considerable portion of the fine coal instead of being projected toward the fire is caught by the swiftly moving stream of gases and is entrained through the fines and thence through the stack in a partly unconsumed state.

To overcome this difficulty, it has been proposed to feed the coal to a point of distribution at the forward end of the firebox so that the finer particles of coal may not be carried oif so readily by the swiftly moving gas currents. While this latter arrangement has demonstrated that reduction in stack losses can thereby be obtained, there are numerous cases wherein the adaptation of this principle of firing cannot be made, due to the fact that the forward end I of the arch within the firebox is set too close to the grates for a satisfactory installation. It has also been found when distributing coal rearwardly from a point adjacent the forward end of the firebox that higher jet pressures must necessarily be used to project coal toward the back portion of the grates; this being due to the fact that the coal, after being projected by the steam jet, loses its initial velocity so that upon reaching the zone of high draft along the back head the finer particles of coal are then carried off by the draft instead of being deposited upon the firebed. To overcome this, a higher jet pressure has to be used in order to insure that the coal upon reaching the zone of high draft is still traveling at a suificient velocity in a horizontal direction to overcome the high velocity of the gases moving along the back head in a vertical direction.

The present invention has for its object the provision of a stoker which is adapted to feed coal to a point of distribution intermediate the front and back portionsof the firebox and at a point beneath the fire so that the fuel is distributed from a point which is removed somewhat from the zone of high vertical draft in order that lower jet pressures may be utilized for projecting coal to all parts of the firebed.

Another object of the invention is to provide a stoker of the underfeed type which feeds fuel upwardly through the grates of the firebox to a point of distribution approximately midway between the front and back walls of the locomotive firebox and beneath the arch thereof.

It is also another object of the invention to provide in a stoker of the type above specified, a fuel distributor which comprises a jet member circumscribing the outlet of the stoker discharge conduit; the jet member having apertures on its outer face which are directed across the upper surface of a table spaced vertically above the grate.

As a further object thereof, this invention contemplates the provision, in the jet member to which reference has been made, a plurality of apertures which are directed in an upward direction toward the axis of the stoker discharge conduit for aiding the uniform and eflicient flow of coal from the stoker discharge conduit to the firing table, from which the fuel is swept to all parts of the firebed by jets of pressure fluid issuing from said jet member.

These and other objects and the inherent advantages thereof will become apparent as the following description of the invention is read in connection with the accompanying drawings, wherein Fig. 1 is a central, vertical, longitudinal section through the rear portion of a locomotive firebox showing the invention partly in similar section and partly in elevation;

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a sectional View taken along line 3-3 of Fig. 1 and Fig. 4 is a view in plan of the distributing apparatus illustrated in the drawings as seen along the line 4--4 of Fig. 1.

Referring now to these drawings, L indicates a locomotive which comprises the boiler l0 having a hollow back wall II, a hollow front wall I2 and hollow side wall such as I3 (Fig. 2), which together with the grates I4 serve to define the firebox [5. The boiler I0 is supported, in part, by a plate member 16 which at its lower end is secured to the locomotive underframe ll.

The grates M of the locomotive firebox are, in this particular instance, arranged in three longitudinal rows spaced transversely of the firebox. The outer ends of the center row of grates 14 are supported in bearer bars such as 18, which also serve to support the inner ends of the side grate sections l4. The outer ends of the side grate sections are supported in a well-known manner along the lower portion of the mudring 9, which supports the firebox [3. An ashpan is disposed beneath the grate l4 and is arranged so that its outlets such as 2!, 22 pass between the locomotive underframe l1.

Extending longitudinally of the firebox between the hollow front wall I2 and the hollow back wall II is a plurality of water-circulating tubes 23. These tubes extend rearwardly and upwardly from the front wall I2 and serve to support an arch 24 which is composed of separable refractory brick 25. The arch 24 at its lower forward end is sealed against the front wall l2, while at its upper rearward end terminates short of the back wall H to provide an opening 25 which extends along the rear portion of the back wall I I for drafting of the fire.

Products of combustion within the firebox pass upwardly through the opening 26 and thence forwardly through tubes 2! carried by the flue sheet 28. in known manner which consists in producing a sub-atmospheric condition within the firebox [5 to cause air tobe drawn into the firebox through the ashpan 23 and thence through and between the grates M. The hollow back wall I! is provided with a firing opening 33 which is disposed above the level of the grates l4 and the cab deck 3!. A pneumatically operated firedoor 32 closes the firing opening 36.

The stoker for feeding coal from the tender (not shown) is indicated generally by S and includes a conveyor 35 leading forwardly from the tender and flexibly connected at 36 to the rearward end of the conveyor 31 which is firmly secured to the frame II. The forward end of the conveyor 3? terminates in an elbow 33 having a discharge conduit 39 mounted thereabove so as to enter the firebox 55 substantially midway between the hollow front wall !2 and hollow back wall H. The elbow 38 and discharge conduit as are disposed between the grate bearer bars I8.

In order to protect the discharge conduit 39 from the heat within the firebox, there is provided a protective grate 48, the forward and rearward portions of which rest upon the grate sections l4, while the lateral portions thereof rest upon the grate bearer bars !8. In order to permit the elbow conduit 38 and the discharge conduit 39 to pass freely through the plane of the grate sections I4 several of these sections lying between grate bearer bars are removed or otherforward end of which terminates within the elbow conduit 38 and cooperates therewith to push the coal upwardl therethrough and through the upwardly extending discharge conduit 38. The di charge conduit 39 is provided at its upper end with an annular flange 42 upon which is seated a pressure fluid jet member 43. The jet head is of circular construction and is chambered internally as at 44 to provide one or more pressure fluid receiving chambers which are adapted to receive fluid under pressure from supply pipes such as 45 and to emit jets of pressure fluid toward various parts of the firebox in a plane substantially parallel with the plane of the grates [4.

A firing table 48 is also seated upon the annular flange 42 of the discharge conduit 39 and has its upper surface 4'! disposed substantially parallel to the plane of the grates l4 and slightly below the jet apertures 48 which are adapted to issue blasts of pressure fluid from chamber such as 44 of the Drafting of the firebox is accomplished distributor jet member 43. By referring to Fig. 7

4 it will be observed that the firing table 46 is generally rectangular in shape so as to provide, in conjunction with the circular configuration of the jet member 43, flat surfaces 49, of relatively greater extent, at each corner of the firing table. This is a desirable construction, as the larger fuel supporting surfaces 49 cooperate with the jet member 43 in projecting coal toward the corners of the rectangularly shaped firebox IE; it being obvious that fuel projected from these enlarged surfaces 49 will travel a greater distance, as it necessarily must do to reach the corners of the firebox.

On its inner portion, the jet member 43 conforms to the internal configuration of the discharge conduit 39 so that fuel may pass therethrough and fall upon the upper surface 41 of the firing table 45 for distribution over the firebed. In order to insure that the column of fuel rising through the discharge conduit 39 and the inner portion of the jet member 43 may not project upwardly beyond the limits of jet member 43 in a consolidated core for a considerable distance vertically, means are provided which operate to cause fuel to fall in front of the jet member 43 in an efficient manner. To accomplish this result there is provided within the interior of the jet member 43 a chambered portion 50 arranged to receive fiuid under pressure from a supply pipe such as E! (Fig. 3). The fluid under pressure within the chambered portion 50 is directed in jet streams through apertures 52 formed in the interior wall 53 of the jet member 43. The jet apertures 52 converge toward the vertical axis of the circular jet member 43 and are directed slightly in an upward direction.

In the operation of this device the fuel is conveyed forwardly and then upwardly by the conveyor screw 41 so as to form a more or less consolidated core within the discharge conduit 39. As the coal rises to a point within the range of the inwardly directed jets of pressure fluid issuing from the converging jet apertures 52 it is carried over the upper edge of the jet member 43 and falls upon the upper surface 41 of the firing table 48. Care should be taken that the pressure of the fluid issuing from the jet apertures 52 is relatively low as it is intended that these jets 52 should be used primarily for the purpose of breaking up of any core formation which may otherwise extend to a considerable heighth above the jet member 43 before breaking off. Of course, if desirable, the pressures of these jets 52 may be varied at will, through known means. Upon being deposited in front of the jets 48 the fuel is projected forwardly and laterally toward all parts of the firebed by being swept off the upper surface 4'! of the firing table 46. It will be observed that since the point of distribution is disposed substantially in the middle of the firebox l5 it will be possible to use relatively low and equal jet pressures for securing even distribution.

From the foregoing, it will be Clear-t0 those familiar with the art that with the present invention a stolzer can be applied to locomotive firerz-oxes beneath the arch regardless of the level of the lower end of the arch. At the same time, efficient distribution of coal to all parts of the firebed is accomplished by relatively low pressure jets.

While but one embodiment of the invention has been illustrated, others are contemplated with the scope of the following claims.

I claim:

1. In a locomotive having a boiler with a firebox therein, a grate for said firebox, said firebox comprising a back wall, side walls and a front wall, and an arch extending upwardly and rearwardly from said front wall toward said back wall, said arch terminating short of said back wall to provide an opening along said back wall for the passage of the products of combustion, a stocker for feeding fuel into the firebox comprising in combination a discharge conduit extending through the grate of said firebox to a point beneath said arch intermediate said side walls, means for urging fuel through said discharge conduit, and fuel distributing means at the upper end of said discharge conduit for projecting fuel over said grate, said distributing means comprising a jet member embracing the upper end of said discharge conduit provided with jet apertures arranged to project fuel radially toward all parts of the grate.

2. In a locomotive having a boiler with a firebox therein, a grate for said firebox, said firebox comprising a back wall, side walls and a front wall, and an arch extending upwardly and rearwardly from said front wall toward said back wall, said arch terminating short of said back wall to provide an opening along said back wall for the passage of the products of combustion, a stoker for feeding fuel into the firebox comprising in combination a discharge conduit extending through the grate of said firebox to a point beneath said arch intermediate said side Walls, means for urging fuel through said discharge conduit, and fuel distributing means at the upper end of said discharge conduit for projecting fuel over said grate, said distributing means comprising a jet member embracing the upper end of said discharge conduit provided with jet apertures on its outer periphery for projecting fuel radially to all parts of the grate, and having jet apertures on its inner periphery for emitting fiuid under pressure against fuel rising through said discharge conduit.

3. In a locomotive having a boiler with a firebox therein, a grate for said firebox, said firebox comprising a back wall, side walls and a front wall, and an arch extending upwardly and rearwardly from said front wall toward said back wall, said arch terminating short of said back wall to provide an opening along said back wall for the passage of the products of combustion, a stoker for feeding fuel into the firebox comprising in combination a discharge conduit extending through the grate of said firebox to a point beneath said arch intermediate said side walls, means for urging fuel through said discharge conduit, and fuel distributing means at the upper end of said discharge conduit for projecting fuel over said grate, said distributing means comprising a jet member embracing the upper end of said discharge conduit provided with jet apertures on its outer periphery for projecting fuel radially to all parts of the grate, and having jet apertures on its inner periphery directed upwardly and toward the axis of said discharge conduit for emitting fiuid under pressure against fuel rising through said discharge conduit.

i. In a stoker mechanism, the combination with a firebox having a grate, of a fuel discharge conduit extending through and above the level of said grate centrally of said firebox and fuel distributing means at the upper end of said discharge conduit for projecting fuel over said grate, said distributing means comprising a jet member embracing the upper end of said discharge conduit provided with jet apertures arranged to project fuel radially toward all parts of the grate.

5. In a stoker mechanism, the combination with a firebox having a grate, of a fuel discharge conduit extending through and above the level of said grate centrally of said firebox and fuel distributing means at the upper end of said discharge conduit for projecting fuel over said grate, said distributing means comprising a jet member embracing the upper end of said discharge conduit and provided with jet apertures, and ledge-like means embracing said jet member for receiving fuel from said discharge conduit, said jet member being provided with jet apertures arranged to project fuel across said ledge-like means toward all parts of the grate.

6. In a stoker mechanism, the combination with a grate, of a fuel discharge conduit extending through and above the level of said grate centrally of said firebox and fuel distributing means at the upper end of said discharge conduit for projecting fuel over said grate, said distributing means comprising a jet member embracing the upper end of said discharge conduit provided with jet apertures on its outer periphery for projecting fuel radially to all parts of the grate, and having jet apertures on its inner periphery for emitting fluid under pressure against fuel rising through said discharge conduit.

RAYMOND L. BE-LKNAP. 

